A common problem in rotary brush units used in vehicle washes is the permanent deformation or breakage of the brush shaft. Frequently, vehicles which stray from the proper path or track or which are too large or driven too fast run into the brushes with excessive force, causing the brush shaft to bend or break.
A typical prior art overhead brush unit 10 shown in FIG. 1 comprises a motor drive unit, drive/support shaft, and brush. The rotating drive shaft 20 is suspended at its upper end 20a from an overhead, motorized drive unit 15. A brush 18 is attached to the shaft at its lower end 20b to rotate with the shaft. Though made of steel or a similar strong material, the drive shaft 20 can be bent when, for example, an automobile 1 runs into the brush 18. If the force of the collision is great enough, shaft 20 can be permanently bent or even broken at a bending moment region 27 between the brush and the drive unit. This type of damage requires disassembly of the entire brush unit 10 in order to replace the damaged shaft; removing the shaft from the drive unit is a particularly labor intensive operation. Such damage is also expensive from the standpoint of both replacement shaft cost and downtime during which the brush unit, and often the entire wash, is inoperative.